As American law-enforcement agencies investigating the Boston Marathon bombings turn their attention to a visit last year to Dagestan by the older of the two brothers suspected in the attack, neighbors of the brothers on Sunday offered an explanation for what Tamerlan Tsarnaev was doing for much of his time in the Russian republic: he was fixing up his father’s home. “He was a normal son helping his father,” Agayev, a neighbor who lives in the same apartment building as Anzor Tsarnaev, the brothers’ father, told TIME on Sunday. “He worked on the remodeling every day he was here, from morning till night.”

The Tsarnaev home is a first-floor property on Oleg Koshelov Street, a rutted lane in the center of the regional capital of Dagestan. Neighbors recalled the 26-year-old suspected bomber, who died in a confrontation with police during the manhunt that ended with his 19-year-old brother Dzhokhar surrendering to police, pouring cement for a walkway and fixing up the interior of the apartment throughout his six-month visit in 2012. His father, who had moved back to Dagestan from the U.S. about two years earlier, was planning to open a perfume shop in the apartment or rent it out as a beauty salon, neighbors said. “We called him ‘the perfumer,'” says one neighbor, who would only give his first name, Vyacheslav, referring to the elder Tsarnaev. “That’s the business he was in.”

So far there appears to be no evidence that links Tamerlan Tsarnaev to any of the Islamist militant groups that have long fought Russia in Dagestan and neighboring Chechnya, but his time there last year is coming under increasing scrutiny, as investigators try to piece together what motivated the brothers. Some media reports have suggested Tsarnaev spent some time traveling in the region during his visit. House Intelligence Committee Chair Mike Rogers, a Republican from Michigan, said on NBC’s Meet the Press on Sunday that Tsarnaev might have traveled to Dagestan under a false name. “It would lead one to believe that’s probably where he got that final radicalization to push him to commit acts of violence and where he may have received training on what we ultimately saw last Monday,” Rogers said.

Reuters TV / Reuters

Anzor Tsarnaev gives an interview in Makhachkala in this video grab on April 19, 2013

Anzor Tsarnaev’s neighbors on Sunday rejected suggestions that Anzor’s son was radicalized during his visit last year. Although most of the neighbors declined to give their names, they were only too eager to defend the Tsarnaevs as upstanding and well-to-do members of the community. They dismissed any talk that Tamerlan, who appears to have posted videos on YouTube of Dagestani militants calling for armed jihad, may have been sympathetic to Islamist extremism. “He went to the main mosque every Friday with his father for services,” says Agayev. “So what? Christians go to church, Muslims go to mosques. There’s nothing radical about that.”

In their eagerness to find some explanation for what happened, the neighbors offered theories that seemed to get ever more elaborate. Vyacheslav at first suggested the most popular theory now floating around Dagestan — that the Tsarnaev brothers were “set up” by American intelligence agencies — but he also said the true conspirators could have been neo-Nazi groups or “private contractors.” Any kind of explanation seemed more plausible to the neighbors than the one coming from television news — that the man they had seen helping his father build a family business had committed a terrorist attack on civilians on the other side of the Atlantic. “I can’t explain it,” Agayev says finally. “But it can’t be what everyone is saying. It doesn’t make any sense.”